My first ADAM - no video

[martin1b]

Ok. I'll get a Z80A on the way. Will check in once installed.

[ChildOfCv]

2 hours ago, martin1b said:

I as able to get it hood up to a monitor, using composite out (FWIW). See below:

Also, I wonder about the lack of color.  It may be necessary to take a closer look at the LM1889 in the RF box, as well as the 4066 (U23) on the board near (or possibly under) the box.

 

If you remove the cap on the RF box, you should see an 8-pin connector.  Pin 8 is the clock input and should be a 3.58MHz sine wave.  Pin 5 should be a bias voltage around 5.8V.  Pin 4 should be +12V.  Pin 3 is the red component and should be an AC signal dancing around pin 5's voltage.  Pin 2 is audio input, and we know from the RF output that that works.  Pin 6 is the B/W part of the signal and should also be dancing around pin 5's voltage.  7 is the blue component and should also be dancing around pin 5's voltage.

 

If it's like the Colecovision, the board will be mounted upside down with the traces on top.  The LM1889 is the dual row of pins in roughly the middle.  Pin 1 of that chip should have a phase-shifted version of the clock signal and pin 18 should be phase-shifted in the opposite direction.  One leads, the other lags.

 

So check if you see any color output on the red and blue especially.  If you do, then you should also see color output on the monitor.

Edited June 14, 2021 by ChildOfCv

[martin1b]

Finally got around to installing the processor. It lives! However, color isn't great. Top pictures below are from the composite out, not the RF out. Hooked up RF and the fuzzy colored pictures are attached (i don't have a great RF setup). So we know at least the color is being generated. Odd the composite isn't color but rf is. 

 

So I popped in a cartridge and got this. Reset both. One comes up with typewriter, other with this. Cycled power, comes up to typewriter. What am I doing wrong?   

 

[ChildOfCv]

That's a huge improvement.

 

First, do you know if the cartridge is good?  Do you have others to test?  Also, I assume you inserted the cartridge with the label facing front, opposite of the 2600.

 

If you're fairly sure the cartridge is good, it's time to check the cartridge pins.  Make sure they are clean and not bent out of shape, so that they can make contact with the cartridge.  Check that +5V is on pin 30 and GND is on pin 29 (remember that the pin ordering is wonky for cartridge connectors--29 and 30 are across from each other.  Make sure you don't short them out while probing).

 

You may also need to check that the address and data lines have continuity with the Z80.

 

Finally, check the cartridge address select lines.  CS1 (pin 18) should pulse a few times just after hitting reset.  This would be the BIOS's reads of addresses 0x8000 and 0x8001 to see if the data there indicates a cartridge is present.  CS2 (22), CS3 (2), and CS4 (27) should all be high.

 

As for the composite color, look at the composite output signal with an oscilloscope.  You should see a sine wave immediately following each sync tip, as in this picture:  

[ChildOfCv]

As for the RF, you can omit the switch box.  Just get a cable like this https://www.amazon.com/Coaxial-F-Type-Connector-Copper-Conductor/dp/B00UG1XA8W and connect it directly to the TV.

 

Edited July 1, 2021 by ChildOfCv

[martin1b]

Nice! Anything helps to bypass that dang switchbox.

 

Ok, so with cartridges, if I tilt them forward, some of the come up. Must be a loose cartridge connection, dirty cartridge, bad solder joint or something else.

 

FWIW, here were my test results : 30 is +5 and 29 is gnd. Haven't yet checked continuity with the processor. Will have to dig up the schematic on that. Pin 18 does pulse (attached video). I'll check 2, 22 and 27 when I check processor cont. 

 

 

Regarding color, are you referring to color burst? I see it in the signal, but the signal looks a bit noisy (see attached)

 

 

 

 

 

[NIAD]

13 hours ago, martin1b said:

So I popped in a cartridge and got this. Reset both. One comes up with typewriter, other with this. Cycled power, comes up to typewriter. What am I doing wrong?   

Congrats on reviving the system and hope the rest of the salvage job goes smoothly.

 

You aren’t doing anything wrong re the Reset switches.

 

- Turning on the ADAM or pressing the Computer Reset (on left side of cartridge port) brings up the Electronic Typewriter mode. Press the Escape/WP key on the keyboard to enter the full word processor (SmartWriter).

 

- Pressing the Cartridge Reset (on right side of the cartridge port) starts up the cartridge that is inserted in the Cartridge Port and if no cartridge is inserted, displays the ColecoVision BIOS (OS7) screen with the message to turn off the system and insert a cartridge. If there are further issues with the ColecoVision PCB, cartridge connector or cartridge itself, you will get this BIOS notification screen.

Edited July 1, 2021 by NIAD

[ChildOfCv]

1 hour ago, martin1b said:

Regarding color, are you referring to color burst? I see it in the signal, but the signal looks a bit noisy (see attached)

The attached looks like the pulses of the cartridge select line.  Did you upload the wrong video?

[martin1b]

@NIAD: Thanks!! I'm excited to see what the ADAM can do.

 

@ChildOfCv

My bad. Thought I attached it. Here is a pic of the video signal.

Edited July 1, 2021 by martin1b

[ChildOfCv]

Can you verify that the monitor has color from other sources like the VCR?  It seems to have two switches, one could possibly be for disabling color.  There is also a "color" knob which you can use to adjust the saturation of the color from B/W to Thomas Kinkade.

 

As for the cartridge connector, you have a couple of options.  One is to attempt to rescue the one you have with tons of Deox-it or other chemicals, reshaping the contacts with a pick, etc.  The other option is to replace the connector.  It would be a 'card-edge connector, Female, 15 place, 30 contact, 0.1" pitch, with mounting holes'.  One I have was built by Sullins Corp.  Model number is EBC15DRTH.  Other beginning letters are okay.  "E" means it's a blue plastic one.  The second letter describes the plating material.  "B" means it has a really thin layer of gold, like maybe a micron if that much.  "C15DRT" part is essential.  The H at the end means it has the mounting holes, so that's highly desirable.

 

You can likely find usable items on eBay or Amazon.

[martin1b]

Yes, RF and composite are both coming into the same monitor. It's actually a USB capture device. RF is through a VCR, into the capture device, which has color. Composite is directly into the device, no color. I'm wondering if the signal is noisy for some reason, causing the color burst to be ignored. 

 

Thanks for the cartridge connector information. Can I ask, how do you know so much about that (and all of this computer)? It's very helpful!

[ChildOfCv]

42 minutes ago, martin1b said:

Yes, RF and composite are both coming into the same monitor. It's actually a USB capture device. RF is through a VCR, into the capture device, which has color. Composite is directly into the device, no color. I'm wondering if the signal is noisy for some reason, causing the color burst to be ignored.

Well, what I see on the scope looks pretty clean.  You could expand the burst itself to see if it looks good.  Set the scope for positive trigger and put the trigger point just above the bottom of the sync pulse, then you should be able to get a stable view of the color burst.  The only thing of note to me though is that it looks slightly weak.  But otherwise it seems to be what it needs to be.

42 minutes ago, martin1b said:

Can I ask, how do you know so much about that (and all of this computer)? It's very helpful!

With few exceptions, this board is a direct copy of the Colecovision, and I have a fair bit of familiarity with it. I bought the card-edge adaptor just to experiment with dumping a CV cartridge.  All the specifics I mentioned about the part number are specified on the datasheet which I found at sullinscorp.com while looking through their edge connector catalog.

[martin1b]

Not having much luck triggering in on the color burst. Here's more of what I show. Perhaps you can see the ghosting in the video signal. I've never seen that before. 

 

 

[ChildOfCv]

The ghosting can be due to the vertical retrace interval where it has one long sync period instead of a bunch of little ones.  That could throw off your timing about 60 times per second.  But even the ghost seems to have a good colorburst signal and a clean sync tip.

 

The signals in the middle are likely other lines which have different intensities.

 

Is it possible to hook the composite directly to that monitor without going through a VCR or adaptor?

[martin1b]

That was it. Must be an issue with the capture device. This monitor did the trick.

 

Thanks for all of the help!!